According to GKN, heating element life improved from 12 months to more than three years, and tube life improved from nine months in the charge end of the furnace and 18 months in pusher zones to more than five years.

Switching to APM elements and tubes had a significant impact on costs. Based on GKN maintenance records, the four six-zone furnaces previously had to be taken out of service three or four times a year, for a week at a time, to replace heating elements and tubes. Today, only two shutdowns a year are required. This saves GKN more than $200,000 annually in lost production. In addition, furnace downtime has been reduced from 31% to 10%; maintenance costs have been reduced by $8,000 a year; annual spending on replacement elements and tubes was reduced by $24,000; and furnace productivity increased by 20%.

Case History #2

When commercial heat treater Bodycote Thermal Processing rebuilt a gas-fired batch furnace at its Minneapolis plant, it replaced cast radiant tubes with Kanthal APM tubes. APM tubes are extruded from an iron/chrome/aluminum powder metal alloy. They have a much longer high temperature service life than conventional radiant tubes. APM radiant tubes also reduce furnace downtime and maintenance costs, and contribute to improved furnace performance.

Case History #3

The Lindure® process is a method of heating that requires precise control of furnace temperature. When Bodycote Thermal Processing introduced the Lindure process to its Indianapolis plant, it contacted Kromschroder, Inc., Hudson, OH, to rebuild a 30″x48″x30″ integral quench furnace.